Fair Value Measurements (Estimated Fair Values Of Financial Instruments Not Recorded At Fair Value In Their Entirety On A Recurring Basis) (Details) - USD ($) $ in Millions		Mar. 31, 2019	Dec. 31, 2018
Cash and due from banks		$ 1,063	$ 1,390
Interest-bearing deposits with banks		2,418	3,171
Total loans, net of allowance for loan losses		49,655	49,492
Demand deposits (noninterest-bearing)		26,242	28,690
Certificates of deposit		2,776	2,131
Total deposits		54,091	55,561
Short-term borrowings		935	44
Medium- and long-term debt		6,848	6,463
Carrying Amount
Cash and due from banks		1,063	1,390
Interest-bearing deposits with banks		2,418	3,171
Loans held-for-sale		2	3
Total loans, net of allowance for loan losses	[1]	49,655	49,492
Customers' liability on acceptances outstanding		4	4
Restricted equity investments		264	248
Nonmarketable equity securities	[2]	6	6
Demand deposits (noninterest-bearing)		26,242	28,690
Interest-bearing deposits		25,073	24,740
Certificates of deposit		2,776	2,131
Total deposits		54,091	55,561
Short-term borrowings		935	44
Acceptances outstanding		4	4
Medium- and long-term debt		6,848	6,463
Credit-related financial instruments		(55)	(57)
Estimated Fair Value
Cash and due from banks		1,063	1,390
Interest-bearing deposits with banks		2,418	3,171
Loans held-for-sale		2	3
Total loans, net of allowance for loan losses	[1]	50,154	48,889
Customers' liability on acceptances outstanding		4	4
Restricted equity investments		264	248
Nonmarketable equity securities	[2]	10	11
Demand deposits (noninterest-bearing)		26,242	28,690
Interest-bearing deposits		25,073	24,740
Certificates of deposit		2,751	2,100
Total deposits		54,066	55,530
Short-term borrowings		935	44
Acceptances outstanding		4	4
Medium- and long-term debt		6,862	6,436
Credit-related financial instruments		(55)	(57)
Level 1 | Estimated Fair Value
Cash and due from banks		1,063	1,390
Interest-bearing deposits with banks		2,418	3,171
Loans held-for-sale		0	0
Total loans, net of allowance for loan losses	[1]	0	0
Customers' liability on acceptances outstanding		4	4
Restricted equity investments		264	248
Demand deposits (noninterest-bearing)		0	0
Interest-bearing deposits		0	0
Certificates of deposit		0	0
Total deposits		0	0
Short-term borrowings		935	44
Acceptances outstanding		4	4
Medium- and long-term debt		0	0
Credit-related financial instruments		0	0
Level 2 | Estimated Fair Value
Cash and due from banks		0	0
Interest-bearing deposits with banks		0	0
Loans held-for-sale		2	3
Total loans, net of allowance for loan losses	[1]	0	0
Customers' liability on acceptances outstanding		0	0
Restricted equity investments		0	0
Demand deposits (noninterest-bearing)		26,242	28,690
Interest-bearing deposits		25,073	24,740
Certificates of deposit		2,751	2,100
Total deposits		54,066	55,530
Short-term borrowings		0	0
Acceptances outstanding		0	0
Medium- and long-term debt		6,862	6,436
Credit-related financial instruments		0	0
Level 3 | Estimated Fair Value
Cash and due from banks		0	0
Interest-bearing deposits with banks		0	0
Loans held-for-sale		0	0
Total loans, net of allowance for loan losses	[1]	50,154	48,889
Customers' liability on acceptances outstanding		0	0
Restricted equity investments		0	0
Demand deposits (noninterest-bearing)		0	0
Interest-bearing deposits		0	0
Certificates of deposit		0	0
Total deposits		0	0
Short-term borrowings		0	0
Acceptances outstanding		0	0
Medium- and long-term debt		0	0
Credit-related financial instruments		(55)	(57)
Nonrecurring
Total loans, net of allowance for loan losses		$ 42	$ 35

[1] Included $42 million and $35 million of impaired loans recorded at fair value on a nonrecurring basis at March 31, 2019 and December 31, 2018, respectively.

[2] Certain investments that are measured at fair value using the net asset value have not been classified in the fair value hierarchy. The fair value amounts presented in the table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the Consolidated Balance Sheets.